Caustic Potash. KO, HO. PotassAe Hydras. Hydrate of Potash (Pharm. Lond.). Called also Potassa Fusa, Lapis Infernalis, Kali Purum, &c. Comp. 1 Eq. Potash = 47,+1 Water = 9 = 56, Eq. Wt
Med. Prop. and Action. Powerful caustic and escharotic; and when taken into the stomach, it acts as a caustic poison. It is never given internally. For external use it is generally moulded into pencils, which should be of a white colour, but are frequently variously coloured from the presence of impurities. One of its chief medicinal uses is in making issues, &c, but the rapidity with which it deliquesces is a great objection to its use. It readily attracts moisture from the atmosphere, and should therefore be kept in closely-stoppered bottles. The mixture of equal parts of Caustic Potash and Lime (Potassa cum Calce) is also used as a caustic. It has the advantage of being less deliquescent than Potassa Fusa. It is used in the form of paste made with spirit.
Offic. Prep. Liquor PotassAe. (See art.)
In Hospital Gangrene, Prof. Res-telle * considers that Caustic Potash is not only the best application, but that it neutralizes the virulence of the poison itself. He employed it with success in 400 cases. On the first day, he applied pieces of the caustic in substance to the wound, endeavouring to penetrate into all its sinuosities. The next day the wound is dressed with a solution of j. ad Aq. fj., and every day the strength is diminished by four or five grains, to the filth day, when the wound is simply dressed. Even the worst cases improved under this treatment. In the subsequent management of the wounds, charcoal, and especially the Carbonate of Magnesia, were of great service.
* Brit. and For. Med.-Chir. Rev., Oct. 1850.
H. Bennett* speaks highly of the value of Potassa Fusa and Potassa cum Calce as local applications. He considers it, however, as a last resource, only to be employed when all other treatment, local and general, has failed. If incautiously or imprudently employed, serious results may follow.